The molt conundrum: Should you say “juvenile” or “juvenal”?

Eastern Bluebirds by Lonna Ours.
Eastern Bluebirds by Lonna Ours.

Kenn Kaufman’s column “ID Tips” appears in every issue of BirdWatching. In our August 2015 issue, he described what to look for to identify juvenile songbirds. He also discussed “subadult,” “immature,” “juvenile,” and “juvenal” — terms often used, and misused, in descriptions of the process by which young birds come by their adult plumage:

BirdWatching Contributing Editor Kenn Kaufman
BirdWatching Contributing Editor Kenn Kaufman

The regular replacement of feathers is a subject so complex that books have been written about it. (Steve Howell’s excellent Peterson Reference Guide to Molt in North American Birds, Peterson Reference Guides, 2010, is highly recommended.) If you read much on the topic, you’ll run across the word juvenal, and the different spelling can be confusing.

In a pioneering 1900 work on plumage and molt, American ornithologist Jonathan Dwight advocated the term juvenal for a bird’s first coat of feathers. He felt that juvenile was too vague and might be applied to any young bird. According to Dwight, juvenal would be more specific to one particular plumage.

His approach held sway for a century in North America, but it was always a source of friction. Some writers used juvenal only when focused on feathers — in other words, “juvenile birds wear juvenal plumage” — providing endless headaches for editors and proofreaders. Others claimed that a bird in juvenal plumage should be called “a juvenal,” and that juvenile could still be used for older immatures. Confusion reigned for decades.

In the meantime, British ornithologists merely insisted that the word juvenile should be used only for birds in this first plumage stage. No separate spelling was needed. This simpler approach is gaining fans in North America. Many recent works on bird ID have dropped the word juvenal, leaving it as a historical curiosity. — Kenn Kaufman, Contributing Editor

Kenn Kaufman’s column “ID Tips,” featuring the photographs of Brian E. Small, appears in every issue of BirdWatching. The article above is an excerpt of a column that ran in our August 2015 issue. Subscribe.

Read other articles by and about Kenn Kaufman.

Read about “Kaufman Field Guide to Nature of the Midwest,” co-authored by Kenn Kaufman.

Read a memorial to Jonathan Dwight published in The Auk in January 1930 (PDF).

 

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